Phase transformation is still one of the most effective and efficient means to produce desired microstructures in materials for various applications. This symposium is a continuation in a series of annual TMS symposia focusing on phase transformations and microstructural evolution in materials during processing and in service. It intends to bring together theoretical, experimental and computational experts to assess the current status of theories of phase transformations and microstructure evolution primarily in the solid states. In addition to fundamental understanding of the mechanisms underlying phase transformations and microstructure evolution; attention will also be given to the utilization of unique transformation pathways to develop novel microstructures for advanced structural and functional materials.